The present invention relates to semiconductor packages and methods of fabrication thereof, and more particularly, to methods of testing a semiconductor package.
Quality is a very important factor in the automated manufacturing of products, such as semiconductor packages. Semiconductor packages having defects at edges of the packages are responsible for a relatively high proportion of returned PBGA (plastic ball grid array) or similar semiconductor packages. One cause of such defects/faults includes damage caused by operator mishandling such as dropping or bending, which can cause cracking of the package. If such damage is minor, that is, it is not noticed by the operator and the package is subsequently used in a manufacturing process, delamination of layers within the package may occur. Delamination may occur for other reasons too. For instance, delamination may arise from irregularities in formation of layers of the package. Such minor cracks and delamination effects are very hard to detect, especially after the parts have been subjected to subsequent assembly processes, such as encapsulation or molding.
Some previous efforts to obviate and/or minimize the effects of such damage include forming a physical barrier in a layer of a package so that any cracks that may appear in an outer edge of the package do not propagate from the package edge inwards towards the center of the package.
The above approach still falls far short of being an optimal solution since the manufacturing process is complicated by the addition of the barrier. Additionally, this technique has limited effect in obviating delamination caused by irregularities in the formation of layers of the semiconductor package.